Animation Shows the Shocking Speed of the Washington Landslide

Nearly an entire square mile was covered by the huge landslide that struck the small town of Oso, Washington in March. The size of this slide is impressive, but it was the speed with which the mud and debris flowed down the hill that made it so deadly.

The slide’s velocity has surprised scientists studying the event. The animation above from the U.S. Geological Survey shows that the debris likely traveled a mile in just 60 seconds, giving people in its path little chance to escape. Keep in mind that the animation is sped up to 20 times normal speed, but just imagine a huge wall of earth coming at you at 60 miles per hour.

According to the Centers for Disease Control, landslides and mudslides typically kill between 25 and 50 people a year in the U.S. The death toll from the Oso slide has reached 36, with 8 people still unaccounted for.

Geologists speculate that a combination of factors were to blame for the slide’s speed and the distance it covered. The same chunk of land moved a little in 2006, which probably destabilized the area. The ground consisted of fairly loose sediments that had been deposited by glaciers. Those sediments were then saturated by an unusually rainy winter, which helped them to liquefy quickly as they flowed down the hill.